Two of the three are probably unnecessary.
If Labour wins the next election, it has promised to carry out a "strategic defence review", looking at what the British armed forces are for and the world in which they will be operating, to determine what organisation and equipment they really need. If we had such a strategic review, it would probably conclude that large-scale war was most unlikely, and that in any such case - a really major breakdown of international order - we would be able to rely on the Americans for some of the more demanding technologies. But most of the time, there would be no direct military "threat" to Britain. Its armed forces would be an instrument of British foreign policy, continually engaged in smaller conflicts around the globe.
Such a review would result in the cancellation of the air-launched anti- armour weapon and the maritime patrol aircraft. We would keep the Conventionally- Armed Stand-Off Missile (Casom). How come?
The anti-armour weapon and the maritime patrol aircraft are, in the main, hangovers from the Cold War. Yesterday's announcement justified them in the usual jargon of defence speak . "The ability to defeat enemy battle tanks and other armoured vehicles will be vital to the success of national and coalition operations. Dramatic advances in armour technology and the proliferation of such technology around the world mean we must possess a highly flexible, rapidly deployable weapon to protect our forces and those of our allies."
When I started work in the Procurement Executive of the Ministry of Defence in autumn 1978, Air Staff Target 1238 - as it was then known; it later became Staff Requirement (Air) 1238 - was already filling the pink files. Eighteen years later, the MoD has finally ordered it. Back in 1978, we believed the Soviet Army was quite likely to swarm across the North German Plain. Large numbers of tanks, so many they filled the battlefield, would present a reasonable target for the Air Force. The idea was to fire air- launched missiles to thin out the echelons of tanks well behind the forward troops, reducing the numbers so that the outnumbered Nato forces on the ground might be able to cope with those that got through. Going for the "follow-on" forces had another important advantage. You did not have to worry about distinguishing between your forces and theirs, entwined in the deadly embrace of the "contact battle". It seemed fair enough, at the time.
But 18 years on, we are not facing Third Shock Army. Admittedly, we faced something not dissimilar, in the Gulf war. The Americans pounded the Iraqi armour dug into the sand with heavy bombers and attacked anything that moved in the desert, including, on occasion, their allies. More British soldiers were killed by the Americans than by the Iraqis.
The Gulf war highlighted the dangers of using aircraft against armoured vehicles. The new stand-off missile, Brimstone, would be ideal for shredding columns of tanks miles behind the front line - but against a single Bosnian Serb tank, hiding in a barn? It is hardly the ideal system for most of the circumstances in which British forces are likely to find themselves.
The most expensive order - pounds 2bn - is for a maritime patrol aircraft to replace the Nimrod, based on the very old design of the Comet, with Nimrod 2000 - the same basic aircraft, but with many new parts. Of the available choices, the Nimrod 2000 makes sense. It is a jet, which is quieter than a turbo-prop, and gives less vibration, which helps when hunting for submarines, but is it really necessary at all?
During the Cold War, Soviet submarines were a particularly nasty threat. They threatened the transatlantic sea lines of communication, linking the European battlefield with north American industrial and political might. They threatened US carrier battle groups. The Nimrods were crucial to the battle with Soviet submarines.
The Russians still make some superb nuclear submarines. But the chances we might have to fight a war with them are remote. They also sell submarines to powers with whom we might be in conflict - Iran, for example. But they will not sell their latest and best Akula-class submarines to those powers. Of course, Nimrod 2000 is a great thing to have, and could also be used to track Iranian conventional submarines or blockade runners defying UN embargoes. But is an aircraft of this cost and complexity, specially designed to hunt nuclear submarines in the Atlantic, essential? No.
Our strategic review would, however, recommend keeping the Casom - the Storm Shadow, built by British Aerospace and Matra of France. A highly accurate, fast cruise missile which could smash into an enemy command bunker or a dictator's palace, it is as effective, in its own way, as a nuclear weapon would once have been. Such a missile could be used in a true strategic role - to eliminate a dictator or paralyse the command and control of a state which had incurred the displeasure of the international community. With the use of nuclear weapons now ruled illegal except in cases where our national survival is at stake, such an accurate, conventional deterrent looks extremely useful. And the missile is fired from a safe distance, lessening the risk of pilots being shot down, captured, tortured, and paraded. One of the key developments in warfare in recent years has been less tolerance of casualties - either "enemy" or our own. That means minimising accidental casualties - so-called "collateral damage" - and keeping our own pilots at a safe distance. Casom does both. And, unlike the anti-armour weapon, it suits the kind of wars we may find ourselves in. Casom would be kept - pounds 600m, not pounds 4bn.Reuse content